Thursday, February 21, 2008

Flow

A week ago I met Zach in Long Beach for a tune up. It was late morning, with the wind at 10 and forecast to build. We were both itching to get out and do a little sailing in advance of the San Diego regatta. So after cursory introductions we rigged and went sailing. Zach's friend Grant jumped in Zach's boat and foiled a bit. Then Zach and I went out and tooled around for awhile, after some fidgeting around with the cable attachment on my boat for a few minutes.

The first bit was really nice, with a steady breeze from an odd direction - south. The wind is almost always westerly in Long Beach, and when it isn't, something is up. In this case, the something was a big veer and fill from the southwest:

Anyway the puffs were magnificent and we had some fun reaching and working upwind. At the end of one long reach I wiped out and Zach gybed away to head back toward shore. I righted my boat on port tack and was about to bear off and follow him when I noticed a bright blue doublehanded cat blasting into sight from the windward side of the island. As I was sailing toward them I thought I'd just watch, as they were REALLY moving in the breeze.

Cats like this aren't a dime a dozen in Long Beach. There are some cat sailors there, but most don't launch from the beach, and certainly not new-looking Nacra 20s with new sails and FRA sail numbers going like bats out of hell! They tacked onto port in front of me and to leeward and I thought, OK, let's see what this blue banana boat can do.

So I sheeted in and started to point with a ton of Veal heel in wind that was probably 18-20 and relatively steady. I expected to reel the cat in but that didn't happen, first because they were damned quick - maybe even faster through the water than I was, though I was pointing a bit higher - and second because I kept climbing away from them when I was really more in the mood for a drag race.

So I sheeted out just a tad and bore off to see how much ground I could make up. Mind you it was a tight reach but the Moth was sailing beautifully with great control thanks to my latest flap mechanism tweaks and I was heating it up as much as I possibly could. Bottom line is that those cats are really quick! I gained on them steadily but not dramatically, keeping them in view about 100 yards off my starboard bow. We sailed like that for probably five or six minutes - the Nacra was hauling the proverbial mail, with both crew fully trapped and the boat nearly flat and under perfect control. The afternoon sun was getting lower in the sky, lighting up the gold sail and the bright blue hulls. I almost forgot what I was doing, just watching that boat fly across the harbor - which is saying something when you are sailing a Moth! But it was one of those Zen-like moments when you completely forget that you are sailing three feet above the water at 20 plus knots and all the balance, rudder and mainsheet work just fades from consciousness. We could have been satellites orbiting some distant planet - it was like I was there but I wasn't the one sailing the boat. And I haven't been smoking any medical marajuana! (It's legal by California state law, BTW).

When the cat was close to the west oil island they tacked, and I decided to take their stern to say hello. They were a bit surprised to see me there, presumably because they had seen me over by the oil island and had not been looking back over their shoulder at 20 knots to see if any other boats were overtaking them! I would have rolled them eventually and if I had been going hard upwind I would have crossed them by a considerable distance after their tack, but it just goes to show what a long skinny displacement hull, tons of righting moment and a big efficient sail can do for a boat - even one that weighs over 400 lb. Impressive beast to say the least.

I later learned at the Moth regatta from some cat sailors that Performance Catamarans (maker of Nacras) has changed into French hands, and that the new owners have moved to town with their families. No wonder they looked so good on the water!

As much as I liked the look of their boat under sail I don't think I'd trade my ride for theirs, however. There is something about a Moth that makes you feel a bit more like a pilot and less like a skipper, and though displacement sailing can be fun, I don't think it will ever be quite the same for me. The stakes are a bit higher in foiling as our crashes are harder and more frequent, but the payoff in speed and the sensation of literally flying the boat are well worth the periodic tumble into the drink.

Saturday, February 2, 2008

Low on Excuses

The essence of vacuum bagging being, well, vacuum, and nearing the point in my own project at which the ability to apply atmospheric pressure in a coordinated fashion might well be a limiting factor, I dragged the Welch Duo Seal out of long retirement to see whether it might be coaxed into suction once again. I procured this pump through the largesse of Big George, who somehow had managed to come into two fifty dollar Duo Seals, but only needed one. So for $50 in 1999 US dollars (roughly equivalent to $400 of today's dollars, at least when it comes to purchasing anything from Australia) I became the proud owner of a somewhat dilapidated Welch Duo Seal 1400. Or I think that is the model anyway - can't really tell because IT DOESN'T HAVE A MODEL NUMBER. THAT'S HOW OLD IT IS. The serial number is 434; I saw one on eBay the other day with a serial number of 107,000 that was made in 1982! Anyway we are dealing with some seriously old machinery here - probably from the 1940s.

After procuring the pump from George in 1999, it sat in one storage facility or another, completely unused, until last week. I had plugged it in and watched it whirr, but had never tested it with a gauge to see exactly how badly - ahem - it sucked. George had replaced some seals on the thing when he bought it, and told me he could never get it to go much beyond 27"Hg, which is pretty poor vacuum from a pump that is theoretically capable of millitorr performance. So my expectations were pretty low.

All the oil had drained out, so after getting some mailed in from Grainger, and a trip to Culver City Industrial Hardware for some plumbing fittings and a vacuum gauge, we hit a balmy 17" of mercury. This was over ten inches Hg shy of where I had hoped I might be, and ten inches of mercury is a lot of mercury - 254mm worth, or a third of an atmosphere. Either aliens had sucked away a third of Earth's atmosphere, or my pump was in tough shape.

Being a pessimist and knowing the pump had not performed perfectly even before I bought it, I decided an inspection was in order. Mind you I had never performed any maintenance on a vacuum pump of any kind prior to this endeavor, but fools rush in as they say. Fortunately, vacuum in 1940 was a fairly straightforward affair, and three wrenches are all one needs to fully disassemble the thing - well, plus or minus.



There is a lot more to the pump than this photo indicates - namely another rotor/stator setup like this one further down the shaft, a bunch of seals, etc. But this is the heart of the matter - a rotor mounted eccentrically within a stator of larger radius, with spring loaded vanes sweeping varying radii as the rotor turns, effectively increasing the volume allocated to a particular number of air molecules 850 times per minute, with the intake rotor exhausting to the exhaust rotor, resulting in some serious vacuum if everything is functioning properly.

Unfortunately, visual inspection failed to demonstrate the source of my evils. So I phoned the repair desk at Capitol City Vacuum outside Washington, DC and basically pled ignorance in hopes that someone would take pity on me and tell me how to make my pump work. Fortunately Frank on the technical desk, aka Jedi Knight of Duo Seals, told me what to buy and what to do.

Basically he told me to get the basic repair kit (because my vanes are metal they don't wear out like the newer ones do) and a can of Vac Seal and put the pump back together. But the critical bit of information is that the stators are ADJUSTABLE. If they are too far from the rotors, the pump will not pump down. We are talking about 0.001" of clearance here, or less.

While I was in there I replaced the shaft ($40) so the seals would work and the pump would stop leaking oil everywhere, and then reassembled the thing. Unfortunately, an earlier "repairman" had overtightened one of the 5/16" bolts holding the intake side of the pump together, so it was not possible to get it tight. A trip to Auto Zone was required to procure the requisite Heli Coil, which worked like a proverbial charm - or at least allowed me to put the pump back together again.



What it did not do was get me enough vacuum. 25" was the fruit of all my labor. I assumed I would have to completely disassemble the pump yet again and readjust the stators, the thought of which made me look around for other projects, like finishing the wiring on the air compressor...

So I did that, fixing the pressure switch in the process, replacing the main tank valve, putting waterproof steel/plastic flexible conduit over the motor wires, and rewiring the mag start. Then I turned my attention back to the vacuum side of things.

In my zeal for applying Vac Seal, I had put perhaps a bit too much on the intake reservoir flanges, and decided to double check the gasket. Sure enough, it had moved out of position. Could this be the source of my troubles? Tracing the original gasket on some new gasket material and cutting on the lines gave me gasket number three, and without Vac Seal this time I reassembled the pump and plugged it in. The result? 30 inches! The atmosphere has returned, and we can breathe again!


I really don't know if I would recommend this course of action to anyone, but for $75 in parts I saved myself the cost of a different pump, or about $300 on eBay last time I checked. This fix was much less trouble than it might have been, and if it had been any more trouble I might have been better off sending the pump in to be overhauled by a professional.

What does this have to do with Moths, you might ask? I find myself asking the same question, and I have come up with the following answer:

Historically, mothing has been a class of do-it-yourselfers, experimenters, and development-minded individuals. Foiling seems to have brought an entire cadre of world-class sailors in, who have little interest in building boats or rebuilding vacuum pumps when they could be out there improving their boathandling. These guys will be super fast, as long as their boats remain competitive. And that is the point: when a new idea comes along, and proves faster than a current production boat, what will all these rock stars do? Will they get new Moths, or will they get grumpy and fork off into one design? Only time will tell whether the shifting sands of development sailing are too unsettling for their one-design taste.

For my part I will say that blogging is yet another time sink that the best builders and sailors seem to have little inclination toward. Sailing, building and blogging each compete with each other for time, to the extent that no one can really do all three at a high level simultaneously without becoming professional. Even then, people like Amac seem to have their hands full with the design, build and sail program, ignoring blogging completely. Rohan sails full time and manages to blog from events in real time, but he doesn't design or build his boats. So these activities are to a certain extent mutually exclusive. This seems like an argument to forget about the internet, and focus on building and sailing. But without blogs, the class loses cohesion, and we lose the ability to live vicariously through each others' experiences, which is a good deal of the fun.

At some point, each of us has to throw down and declare our loyalties. Personally, I like figuring out how things work, and how to build things myself. I also like the design process, and I like interacting with people who think about design. So it should be no surprise to find me smelling of acetone, covered in vacuum oil, swearing over the radio at myself for having forgotten yet again to install the shaft keys before bolting the stators on for the fifth time.

I have followed the Moth class for years because it seemed to be filled with other people who could have a good laugh at themselves and their tiny boats while moving design further down the track - people for whom a good stack is almost as much fun as winning a race, and who like to build boats almost as much as sailing them. I eventually bought a Moth and started sailing in the class for much the same reason, although the advent of foiling hastened that involvement. To the extent that recent trends seem to be moving the composition of the class more toward professional sailors, and away from designers and builders, the fleet becomes less attractive to people like me. But that is no fault of the class, and it certainly moves the sailing itself up several levels, which is great. In any event, the Moth continues to be a development boat, and develop it will - probably faster than many expect. Interesting times ahead!